While most modern AC units are equipped with the ability to produce both cool air and warm air, it’s not entirely uncommon for poorly maintained or damaged air conditioners to disregard their intended settings and default to blowing uncomfortably hot air. In addition to the discomfort and potential damage this type of malfunction entails, it can also be incredibly frustrating and even dangerous for homeowners and their fellow inhabitants, especially if and when it occurs in the midst of extreme temperatures, as is often the case.

 

When dealing with an air conditioner that’s blowing hot air, it’s important to understand all off the underlying causes that could potentially be to blame. There’s a wide range of possible culprits, from minor mishaps requiring quick DIY fixes to major malfunctions in need of professional intervention. The more familiar you are with the usual suspects, the quicker you’ll be able to identify, troubleshoot and fix the issue.

 

In addition to helping you answer the question Why is My Air Conditioner Blowing Hot Air?, by identifying and diagnosing the problem, this article will also help you solve said problems and distinguish between what you can fix on your own and when it’s time to call in a professional.

 

Diagnosing the Issue

The very first step to fixing any problem with your HVAC system is to identify the cause of the problem. Think of your air conditioner like a patient and the hot air it’s blowing as a symptom. Before you can treat the patient and alleviate the symptom, you have to diagnose their problem them by strategically locating the source of the symptoms.

 

Since certain causes are much more common and quicker to fix while others are the total inverse, it’s important to go in order via a process of elimination to ensure you don’t waste time by overlooking what could have been a simple solution. To make things easier for our readers, we’ll do our best to cover these issues in said order.

 

When to Call a Professional HVAC Technician

The first few troubleshooting steps we’ll cover are simple enough that most homeowners would probably prefer to handle them DIY-style as opposed to calling (and likely paying) someone to do it for you, while some of the bigger issues we’ll cover later should only be handled by trained HVAC professionals.  That said, where exactly you draw that line is ultimately up to you and your level of comfort. The best general rule of thumb we can offer in this regard is that it’s better to be safe than sorry, so if you’re not 100% comfortable handling something on your own, it’s usually best to leave it to the pros.

9 Common Causes of AC Blowing Hot Air & Initial Troubleshooting Steps

1. Thermostat Settings

Explanation:

Believe it or not, if it feels like your AC system is blowing hot air, the most likely explanation as to why it’s doing so is that you’re telling it to – or at least your thermostat is. As such, the very first thing you should check if this happens is your thermostat settings. You may mind find that someone either turned the temperature to an unseasonably high setting or unwittingly switched the system from cooling mode to heating mode.

Troubleshooting:

Check your thermostat settings, correct any unwarranted spikes in your temperature settings and ensure that the system is set to cooling mode. If your thermostat settings are normal and your system isn’t corresponding accordingly, a number of other issues could be the cause.

DIY or Call a Pro: DIY

This super simple step is really a no-brainer, but we get that some folks simply don’t mesh well with technology. However, if you’re having trouble figuring out the settings on your thermostat, you may be able to save some money by consulting the user manual or calling the company that made it before calling in a professional.

2. Unit Reset

Explanation:

Just like computers and video game consoles that slow down and malfunction when they overheat, air conditioners aren’t immune to system overloads and the problems that come with them. It may sound silly and over-simplified, but if your settings are normal and your system isn’t working quit right, sometimes all your system needs is a quick reset.

Troubleshooting:

To reset your AC unit, turn your AC off at the thermostat, then locate the system’s power button/switch and press/flip it to shut the AC system down. Go to your circuit breaker and flip the breaker for your AC unit to the off position, wait a minute, then turn the breaker back on and restart your AC unit. If your system’s problems persist after the reset, the problem lies elsewhere.

DIY or Call a Pro: DIY

This is a super simple test that most homeowners should be able to handle on their own no problem as long as they follow the steps mentioned above.

3. Dirty Air Filter 

Explanation:

The root of many a problem when it comes to home HVAC systems, excessively dirty air filters can become clogged with dirt and debris to the point that they begin to obstruct and restrict the air flow throughout your entire house, leading to what feels like extremely weak or even hot air coming through your vents and registers.

Troubleshooting: 

Check your air filter/s for moderate to excessive buildup and clean or replace with fresh filter/s as needed. On centralized AC systems, the air filter is typically located in a duct on the return line or furnace. Ductless systems usually feature reusable filter on the condenser outside, and window unit filters are normally behind a grate on the front of the unit.

DIY or Call a Pro: DIY

Changing your air filters is something you should already be doing yourself on a regular basis (so long as you’re able), so doing it here should be no different.

4. Obstructed Air Vents & Registers

Explanation:

Just as dirty air filters can obstruct and restrict air flow in a way that makes the air in your home feel hot, the air that does make it through your filter can be equally compromised by the air vents and registers to which it flows.

Troubleshooting: 

Check your home’s air vents and registers for any obstructions (external or internal), blockages or clogging from excessive buildup of dirt and debris. Move the former accordingly and remove the latter by dusting or vacuuming the vent or register.

DIY or Call a Pro: DIY

You should be able to handle this one on your own for the most part. If you find a vent or register is blocked by large furniture, it may be wise to phone a friend, but that friend doesn’t necessarily need to be an HVAC pro.

5. Blocked Condenser Unit

Explanation:

As the main intake, conditioning and distribution mechanism for your home’s air on most systems, the outdoor condenser unit plays a pivotal role in the quality and quantity of air in your system and home at any given time. As such, anything blocking or obstructing your condenser unit can seriously compromise the level of both.

Troubleshooting:

With your AC system turned off, remove any large obstructions, garbage, lawn debris and/or encroaching plants in the immediate vicinity of your condenser unit. If anything is stuck in the fins, remove it by hand or with a broom.

DIY or Call a Pro: DIY

Similar to clearing your vents and registers, this step is relatively straightforward and can usually be completed with relative ease so long as you have the right tools and the physical capacity required to remove any obstructions.

6: Dirty Evaporator & Condenser Coils

Explanation:

Evaporator and condenser coils are the key to your condenser unit’s ability to change warm air into cool air. Just as debris around your unit can compromise the quality of your air, dirt and debris can accumulate within your unit and on your coils, disrupting airflow, reducing the effectiveness of your coils and your compressor,  and ultimately causing your vents to blow out hot air.

Troubleshooting:

To check for dirty coils, simply peer into your condenser unit with a flashlight, or open your unit’s side panel to take a closer look. For a thorough cleaning, use a hose to spray down the outside of your condenser unit, then remove the unit’s side panel to reach the coils inside and repeat, rinsing until the water runs clear.

DIY or Call a Pro: Call a Pro

This step could go either way depending on your level of comfortability with this type of maintenance, but many homeowners are understandably apprehensive about opening up their units and spraying down the contents, so unless you’re only spraying down the outside we recommend leaving this one to a professional.

7. Refrigerant Issues

Explanation:

Refrigerant is the chemical agent that your condenser coils use to cool (or refrigerate) air. Since every system’s supply of refrigerant is finite, when air conditioners are blowing hot air, it often has to due with depleted refrigerant levels. These low levels could mean you’re in need of a recharge (AKA refill), or they could be caused by a leak somewhere in your lines.

 

Either way, refrigerants like freon can be highly toxic, so don’t mess with them at all unless you’re trained and certified to do so. It’s important to leave this step to a professional HVAC tech who can check your levels, find and repair leaks, and recharge your system’s refrigerant without compromising anyone’s safety.

 

Recharging refrigerant is a common service offered by most HVAC companies, but it’s also a potentially dangerous process due to the potentially hazardous materials involved. When an HVAC tech recharges your refrigerant, the chemical is added to your system in a gaseous state via a refrigerant tank that’s hooked up to a supply line within your condenser unit, where it will then be converted to a liquid state with an incredible ability to absorb heat and change temperatures.

Troubleshooting: 

While you shouldn’t try to fix anything to do with your system’s refrigerant, there is one way you can check to see identify if this may be the cause of your problems. In addition to the hot air your system is blowing, a frozen refrigerant line (the largest pipe leading from your home into your AC’s condenser unit) is another sign that could indicate your refrigerant levels are low.  You can even test this by turning your system off and giving the pipe time to thaw, then turning it back on to see if the problem persists. If it does, and your line re-freezes, your system may be leaking or running low on refrigerant.

DIY or Call a Pro: Call a Pro

As mentioned, to avoid potentially harmful toxic chemicals, everything past the basic identification stage should be left to a trained professional on this step.

8. Compressor, Capacitor or Relay Problems

Explanation:

Often referred to as the heart of the system, AC compressors convert power into energy and circulate the refrigerant needed for heat transfer to occur. AC capacitors also play a vital role in this process by supplying and regulating the power needed to make it all happen, while your relay is responsible for connecting and enabling the two to work in tandem. Simply put, without all three of these crucial components functioning properly, your system loses its ability to produce cold air, prompting it to blow hot, unconditioned air into your home until proper function is restored.

Troubleshooting:

Dirty coils, too much or too little lubricant, dirt and debris in your condenser unit, blocked or improperly sized suction lines and refrigerant leaks can all lead to issues with these components, but they can also all be worn down and rendered useless with enough time and use. In the best case scenario, small parts may need cleaned, repaired or replaced. In the worst case scenario, it could be due to total compressor failure as a result of overheating or extended use. In any case, identifying and fixing these issues is best left to professionals, so there’s not much you can do on your own with this one.

 

A total compressor failure is the worst case scenario because it’s one of the most expensive components in your entire system, and a full replacement could cost you thousands of dollars. That said, if your compressor fails and you’re forced to replace it, depending the age and state of the of the unit as a whole, it may make more sense to replace the entire thing as opposed to just the compressor.

DIY or Call a Pro: Call a Pro 

Dealing with these components can be extremely risky due to how expensive they are, and messing with them could easily do more damage than good, so we recommend leaving this one to the pros. If you think your system’s compressor, capacitor or relay may be having issues, call an HVAC tech ASAP.

 

9. Electrical and Wiring Problems

Explanation:

So you’ve exhausted all other possibilities and your air conditioner is still blowing hot air, which leads us right back to where we started: your thermostat – only this time the problem’s a little harder to find and a lot harder to fix.

 

If nothing else seems to be the matter but your air conditioner still won’t respond according to the settings you see on your thermostat, there could be a fault somewhere in the wiring that connects your system’s various electrical components, from your thermostat and the sensors that feed it its information, to your condenser unit and the electrical components that power its most basic functions.

 

All of these electrical components act like one big brain, the many parts of which should be wired to work together in perfect tandem with one another. However, one small fault in this wiring can disrupt the harmony and proper brain function of the entire operation. In other words, your system’s wires are being crossed both literally and figuratively.

 

The good news is, simple wiring issues and even thermostat replacements are relatively cheap operations as far as HVAC repairs go. The bad news is these simple issues could be connected to or causing other, more expensive issues like compressor failures and total system shutdowns.

Troubleshooting:

This issue is hard to identify outright unless your trained in what to look for and how to find it, and messing with wiring and electrical components on high voltage equipment like air conditioners is extremely dangerous, so this is another problem that’s best left to professionals.

DIY or Call a Pro: Call a Pro

As mentioned, air conditioners are extremely high voltage, and messing with their wiring and electrical components is extremely dangerous, so this step should be left entirely up to a professional who knows what they’re doing.

3 Tips to Prevent Future Problems

1. Schedule Regular Professional Maintenance

One of the best ways to prevent yourself from having to deal with any of these problems in the future is to schedule regular maintenance from HVAC professionals. This type of maintenance includes system inspections and rejuvenative services such as cleanings, replacements and basic repairs. It’s recommended that homeowners schedule appointments with HVAC professionals on a bi-annual basis at the very least.

2. Keep Up with DIY Maintenance

As important as it is for homeowners to keep up with regular professional maintenance, it’s equally important that you maintain your AC systems through regular DIY maintenance. Things like cleaning  air vents and registers, clearing debris around the condenser unit and changing air filters on a regular basis are all quick, easy ways to stay on top of your system’s health and help it function properly for as long as possible.

3. Consider an AC System Upgrade

As mentioned, many of the issues covered here become unavoidable due to wear and tear after enough time and use, regardless of maintenance. The older an AC system and its components are, the more problem prone they’ll be, so one of the best ways to prevent issues like this moving forward is to consider upgrading your system once its time has come. This also makes more financial sense after a certain tipping point, as you could spend more money repairing and maintaining an old system than you would investing in a brand new system. On average, depending on the level of maintenance and frequency of use, most HVAC systems have an average lifespan of 10-15 years, so if your system is nearing this threshold it may be time to consider upgrading.

Recap & Closing Thoughts

Just to recap all the of the information covered thus far, there are nine common causes you should check for if your air conditioner is blowing hot air. The first five causes – thermostat settings, unit resets, dirty filters, clogged vents and obstructed condenser units – are all relatively simple find-and-fix solutions that most homeowners should have no problem troubleshooting on their own, while the final four causes covered – dirty coils, depleted refrigerant levels, compressor/capacitor/relay issues and faulty wiring or electrical errors – are all problems that are best left to professionally trained HVAC professionals.

 

If you’re experiencing any issues with your air conditioning – blowing hot air, weak air, dirty air, no air, etc. – it’s important to identify and address such issues as promptly as possible to prevent them from snowballing. Whether doing it yourself or hiring a professional, it’s important to take action ASAP and be a proactive part of the solution. The longer you wait to solve a problem, Left unaddressed, HVAC issues beget bigger HVAC issues. The longer you wait to address a problem, the more time it has to worsen and spread to other parts of your system, and the more you’ll be paying for repairs.

 

Regardless of the issue, it’s never a bad idea to consult a trained professional for HVAC maintenance, especially if you want to catch problems early on. If you’re not 100% confident in your ability to solve a problem on your own, then professional intervention is a must to ensure proper maintenance moving forward. Despite the initial costs, routine professional maintenance can save you a ton of money in the long run by stopping problems at the source, extending the life of your system, and preventing expensive repairs and system failure.

Additional Resources

If you’re a Delaware resident looking for affordable professional HVAC maintenance you can depend on, look no further! The air experts here at Maichle’s have you covered. Click to learn more about our company and schedule a FREE estimate, or call (302) 328-4822 for 24/7 emergency HVAC service!

 

Thanks for reading! For more tips and tons of super informative, easy-to-read articles about all things HVAC – from DIY maintenance and common issues to helpful troubleshooting techniques, energy-saving tips and much more – check out our HVAC ARTICLES section or click on the articles below!

 

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